US20150129550A1 - Circuit breaker gas directing system - Google Patents

Abstract

A gas directing system for a circuit breaker is disclosed. The system includes an insulative housing that fits over vents that convey hot gases upon operation of the circuit breaker. The housing has phase partitions that separate phase sections from one another, and transverse partitions that separate a venting sections for each phase from terminal sections. Gas diverting structures are provided in the venting sections that redirect hot gases towards apertures through which the gases vent. The overall structure may be much lower profile than previous design spacing requirements.

Description

BACKGROUND
• The present invention relates generally to the field of circuit breakers and gas directing and venting arrangements for circuit breakers. More particularly, the invention relates to a system for redirecting and venting hot gasses and conductive materials during operation of a circuit breaker.
• Many applications exist in the industry for switching devices, including circuit breakers. In general, circuit breakers provide protection for wiring and various downstream components by limiting current from electrical sources, such as the power grid. In many industrial settings, three-phase breakers are used in which three-phase power is routed to a load through the circuit breaker hardware. The circuit breaker can be closed to complete the power path to downstream equipment, such as motor drives, switchgear, motor starters, and so forth. Upon occurrence of certain events, the circuit breaker may be caused to open, interrupting the current for all three phases. In most applications a manual reset is provided allowing operations personnel to re-close the circuit breaker after opening to re-enable the operation. In many applications, the circuit breakers may also be manually opened by actuation of a lever, knob or other interface hardware.
• One challenge presented in the design and use of circuit breakers, particularly in industrial or similar enclosures, involves the proper venting of heated gases during operation of the circuit breakers. That is, when opened, contacts and surrounding structures are heated significantly due to the let through energy between the initiation of opening and the extinguishing of all current through the device. Material may be vaporized in this process, and gas may be ionized, such that venting includes both hot gases and conductive ions (e.g., plasma). In many circuit breaker designs, manufacturers may suggest clearance or proximity limits to allow space for venting. However, these impose undesirable constraints on space within enclosures. Also, free venting of hot gas from circuit breakers may adversely increase internal pressures within enclosures, particularly when these are confined, as in many applications. The pressure increases are exacerbated by high rates of increase in pressure owing to the free venting.
• There is a need, therefore, for improved designs for use in circuit breaker applications that can address such drawbacks.
BRIEF DESCRIPTION
• The present disclosure provides a system designed to respond to such needs, in accordance with one aspect, a circuit breaker gas directing system is provided that comprises an insulative plastic housing configured to be fitted over a gas-venting portion of a circuit breaker. Phase separating partitions are disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase. Gas directing partitions separate each venting section from a phase terminal sections for each respective phase. Apertures communicate each venting section with the surrounding environment.
• In accordance with another aspect of the disclosure, a circuit breaker gas directing system comprises an insulative plastic housing configured to be fitted over a gas-venting portion of a circuit breaker. Phase separating partitions are disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase, and gas directing partitions separate each venting section from a phase terminal sections for each respective phase. Apertures communicate each venting section with the surrounding environment. The venting sections are shaped to contain venting gas and thereby to limit a rate of rise of gas pressure on a surround environment side of the apertures. The plastic housing, the phase separating partitions, and the gas directing partitions comprise a single molded piece.
• The disclosure also provides a circuit breaker gas directing system comprising a circuit breaker having phase vents that vent gas upon operation of the circuit breaker, and a cover. The cover is fitted over the phase vents and comprises an insulative plastic housing, phase separating partitions disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase, gas directing partitions separating each venting section from a phase terminal sections for each respective phase, and apertures communicating each venting section with the surrounding environment.
• The techniques set forth in the present disclosure also provide an electrical system, such as a motor control center, that includes one or more circuit breakers and the related gas directing system as disclosed.
DRAWINGS
• These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
• FIG. 1 illustrates an exemplary circuit breaker assembly in an enclosure as might be used in connection with industrial equipment;
• FIG. 2 is an exploded view of the same assembly with a front panel and side panel removed to reveal a circuit breaker and certain of the operating mechanisms;
• FIG. 3 is a perspective view of an exemplary circuit breaker of the type shown inFIG. 2 illustrating an exemplary operating assembly, and cover as disclosed herein;
• FIG. 4 is an exploded view of the same circuit breaker assembly illustrating various operating, gas directing, and position adjusting components;
• FIG. 5 is a similar rear exploded perspective view of the device;
• FIG. 6 is an exploded view of the same circuit breaker with an exemplary gas-directing cover;
• FIG. 7 is a bottom perspective view of the gas-directing cover;
• FIG. 8 is a top perspective view of the gas-directing cover;
• FIG. 9 is a rear view of a mounting base with an adjustment system installed for adjusting position of the circuit breaker with respect to support, mounting and operating hardware;
• FIG. 10 is a rear perspective view of the same arrangement with an adjustment plate exploded from the base to illustrate its features;
• FIG. 11 is an exploded view of an exemplary operating system including a bail, a base, and the interposed circuit breaker;
• FIGS. 12 and 13 illustrate the exemplary bail and base illustrated inFIG. 11; and
• FIGS. 14-16 illustrate an alternative embodiment of a gas directing circuit breaker cover designed for a 4-pole circuit breaker.
DETAILED DESCRIPTION
• FIG. 1 illustrates an exemplarycircuit breaker assembly10 that utilizes components and features that are in accordance with the present disclosure. The circuit breaker assembly may be used in a wide range of settings, including industrial settings, commercial settings, and in various applications, such as manufacturing, material handling, transportation, process industries, and so forth. In many applications the circuit breaker assembly will be installed in anenclosure12, and this enclosure or components included in this enclosure may be, in turn, installed in a larger enclosure and system. In certain industrial settings, for example, such circuit breaker assemblies may be installed in motor control centers (MCCs) used to control operation of one or more motors driven to perform automation tasks. In many of these applications operator handles14, knobs, or similar mechanical devices will be provided to allow for opening and closing (and resetting) of the circuit breakers during normal operation. These will commonly be provided on or near an exterior surface of the enclosure to allow operation without opening the enclosure. For example, in the illustration ofFIG. 1, the operator handles14 protrude from afront panel16 of the enclosure, such as throughapertures18.
• It should be noted that the present disclosure is intended to extend to and enable the inclusion of circuit breakers and the related techniques disclosed incorporated into electrical equipment and systems, particularly MCCs. Detailed descriptions of such MCCs are provided in U.S. Pat. No. 8,553,395, entitled Motor Control Center Network Connectivity Method and System, issued on Oct. 8, 2013 to Blodorn, et al., and U.S. Pat. No. 8,420,935, entitled Bus Support System for a Motor Control Center, issued on Apr. 13, 2013 to Malkowski, Jr. et al., both of which are hereby incorporated into the present disclosure by reference. As will be appreciated by those skilled in the art, such systems typically include one or more enclosure sections, encased in a metal cabinet provided with a sealed door. The components of such systems are grouped into bays or drawers, and advantageously may be fairly densely packed. The present techniques allow for use of the circuit breakers in these systems, provide for withstanding the demanding applications associated with MCCs, particularly positioning and venting during operation, and where desired may enable a more dense packing than previous approaches.
• FIG. 2 illustrates the same exemplary arrangement in an exploded view. In this view, thehandle assemblies20 are illustrated with thehandles14 for two circuit breaker assemblies shown in different positions. Aside panel22 has also been removed to expose thecircuit breaker24 itself, along with anactuating linkage26 andoperating assembly28 for opening and closing the circuit breaker by movement of theoperator handle14. It should be noted that in this view certain components have been removed for clarity, such as biasing springs used to bias the mechanism in a desired position. Theactuating linkage26 is mechanically coupled to the operator handle14 and may be pushed or pulled by movement of the operating handle to move the circuit breaker operating assembly between its opened and closed positions. In the illustrated embodiment the operatingassembly28 includes abail30 and a base32 that are linked together and that interface with the circuit breaker as described below to open and close the circuit breaker. Various linkages and mechanical structures may be devised for actuating the bail and thereby circuit breaker, and the particular construction and arrangement of these is generally beyond the scope of the present disclosure.
• FIG. 3 illustrates thecircuit breaker24 removed from the enclosure and disconnected from the operating linkage and other mechanisms. In this exemplary embodiments, the circuit breaker itself comprises ahousing34 that receives power from a power source (e.g., the power grid) and that provides power to a load (e.g., a motor). In particular, in this embodiment line-side connections are made in an upper portion of the circuit breaker, and load-side connections are made in a bottom portion of the circuit breaker. The load-side connections are separated byphase separators36. Similar separations are made on the line side.
• The operatingassembly28 here comprises thebail30 and a base32 which is connected to and pivotally supports the bail. Thebase32 allows for mounting and securely holding the circuit breaker in place, while the bail allows for switching the circuit breaker between its operative positions. In the illustrated embodiment, the circuit breaker has several operative states, including “on”, “off”, “tripped”, and “reset”. The bail and the base are made of an insulative plastic material, typically molded into their final shapes. In accordance with presently contemplated embodiments, the bail and the base are made of the same molded plastic material, and each generally comprise a single piece of molded material. Suitable materials for the bail may include, for example, a glass filled polyacrylamide, such as Ixef 1022, although other materials may also be used. Suitable materials for the base may include a polyethylene terephthalate (PET), such as Rynite FR945. As used herein, the term “insulative” connotes that the material will not conduct charge when exposed to or contacted by a potential difference, such as hot gas or ionized material vented by the circuit breaker during operation.
• The illustrated bail comprisessides38 and40 that approximately enclose the circuit breaker, as well as afront side42. Aslot44 is formed in the front side and receives atoggle lever46 extending from the circuit breaker that enables the bail to move the toggle lever when the bail is rotated with respect to the base, thereby switching the circuit breaker between its operative states. Agas directing cover48 is provided on an upper side of the circuit breaker, in the illustration ofFIG. 3, and allows for directing and venting gasses produced upon opening of the circuit breaker. The gas directing cover also houses terminals for connecting three phases of line power to the circuit breaker.
• FIG. 4 illustrates the same arrangement in exploded perspective. Here thebail30 has been removed from thebase32 and its sides, general shape, and slot44 can be seen. Thecover48 has also been exploded upwardly to reveal the upper components of the circuit breaker. In the illustration ofFIG. 4, vents can be seen that allow gas to escape from the circuit breaker during operation. As will be appreciated by those skilled in the art, such gasses typically include ionized particles and plasma that is eventually cooled, but that that may be generally conductive as it exits the device. In the illustration ofFIG. 4, for example, side vents50 can be seen as well as upper vents52. The upper vents52 generally allow for gas to escape from each separated phase section within the circuit breaker. The provision of the insulativeplastic bail30 allows for the escape of such conductive gasses fromvents50 and from any other vents around the circuit breaker without transmitting charge to a conductive moving part (the bail and the base being non-conductive).
• Beneath thecover48, in the illustration ofFIG. 4, can be seen also the line-side terminals54. Multiple entry points and forms of connection can be provided for connecting phase conductors to these terminals.
• Also in the embodiment illustrated inFIG. 4, apivot aperture56 is seen on a near side of thebail30, with a similar aperture being provided on the opposite side. The pivot apertures allow the bail to pivot on protruding pivot pins58 of the base that are provided onextensions60.
• Moreover, in the illustration ofFIG. 4, anadjustment plate62 can be seen exploded from a rear of thebase32. As discussed in greater detail below, this adjustment plate allows the circuit breaker to be fitted loosely to the base, and then adjusted in a position (e.g., upwardly and downwardly) to improve its position with respect to other actuating components. Theadjustment plate62 operates with an adjustment screw to provide the desired continuous adjustment of the circuit breaker position.
• These same components are further illustrated inFIG. 5. Here, the bail is again exploded from the base, withpivot apertures56 being visible that interface with corresponding pivot pins58 of the base. The upper gas vents52 are further seen beneath thecover48. Theadjustment plate62 and threadedadjustment screw64 are shown exploded from arear side66 in which they are lodged during assembly and operation.
• FIGS. 6,7 and8 illustrate details of an exemplary embodiment of thegas directing cover48 designed to fit on the circuit breaker and to direct gas vented upon opening of the breaker. As shown inFIG. 6, the cover comprises ahousing68 which is made of an insulative plastic material, such as a fiberglass filledflame retardant Nylon66. The cover fits over both theupper vents52 and theterminals54 of the circuit breaker. Afront side70 of the cover is traversed by ventingapertures72 that allow hot gasses and conductive material to vent from each of the separate phases of the circuit breaker upon opening. The cover of the circuit breaker may be provided withknockouts74 which are panels or regions bordered by weakened or thinner areas that allow certain portions to be easily removed where wiring is made through the cover. Alternatively, conductors may be passed through a backside of the cover opposite the front70. When provided, the knockouts will provide openings having a width of approximately 12 mm.
• The internal configuration of the cover is best illustrated inFIG. 7. Here again, thecover48 comprises a plasticinsulative housing68 with sections for each electrical phase. The sections are formed byphase separation partitions78 which extend longitudinally along the housing.Gas directing partitions78 are formed transversely to these phase separation partitions. The resulting internal structure effectively defines ventingsections80 on a side of the gas directing partitions nearest theapertures72, and phaseterminal sections82 on an opposite side of the gas directing partitions. In the illustrated embodiment, then, gasses that vent from the circuit breaker upon opening are confined within the ventingsections80, and each venting section is separated from neighboring venting sections by the phase separation partitions. This allows for gas to vent only through theapertures72 and not rearwardly toward the terminals. Moreover,gas diverting structures84 may be integrally formed within each venting section to control the flow and pressure of the gas when venting. In a presently contemplated embodiment, for example, the configuration of the venting sections, including the partitions, the diverting structures and the apertures allow for an increase in the gas pressure (i.e., back pressure) that confines the gas and limits the rate of increase of pressure in the atmosphere surrounding the circuit breaker when venting. This may effectively limit the rate of rise of pressure within the enclosure, confining the gas as it escapes to the restricted volumes of the circuit breakers and the venting sections until all gas pressure has been equalized.
• The cover is designed to fit snuggly on the circuit breaker by virtue of thephase separation partitions76 andtabs84 formed at their lower extremity. These tabs may slip within grooves88 (seeFIG. 6) formed between the phase sections of the circuit breaker. The resulting structure provides for containment of venting gas, direction of the gas, control of the gas pressure, and separation of the venting sections from the phase terminal sections.
• As illustrated inFIG. 8, a venting gas is redirected generally along a 90 degree redirection path from an upper direction in the figure outwardly through theapertures72, as indicated byarrows92. This redirection is aided by the divertingstructures84. By virtue of the re-direction, gas containment, and gas separation, the cover may be made in a very low profile as compared to existing circuit breaker vent arrangements.Dimension90 represents the height of the cover above the height of the circuit breaker. In presently contemplated embodiments, theheight90 may be on the order of 25 mm, while without the cover a spacing of approximately 100 mm would have been required. This reduced height allows the circuit breaker and the overall assembly to be placed in smaller and more densely packed arrangements within enclosures.
• A presently contemplated arrangement for the adjustment of the position of the circuit breaker is illustrated inFIGS. 9 and 10. As discussed above, aninsulative base32 allows for mounting of the circuit breaker and the bail. The circuit breaker, however, may need to be adjusted in position relative to this base and bail. To allow for such adjustment, theadjustment plate62 is provided in arear recess94 of the base.Fasteners96 extend through the adjustment plate and traverse the base, and are fastened to the circuit breaker housing. Certain of these fasteners may allow for initial fixation of the adjustment plate to the base, such asrivets98. Other fasteners will typically include screws that extend through the adjustment plate and the base, and into the corresponding apertures provided in the circuit breaker housing.
• The adjustment plate in the illustrating embodiment is generally Z-shaped so as to provide good support on either side of a centerline of the circuit breaker. In the illustrated embodiment, anupper portion100 of the adjustment plate supports the circuit breaker to one side of the centerline, while alower portion102 supports the circuit breaker on an opposite side. Features may be provided in the adjustment plate and the base to afford alignment and to maintain alignment as the plate and circuit breaker, together, are moved with respect to the base and bail. In the illustrated embodiment, for example, analignment slot104 is provided in the adjustment, while acorresponding alignment protrusion106 extends from the base. These structures are illustrated both inFIGS. 9 and 10.
• Adjustment of the position of the circuit breaker proceeds as follows. Initially, the circuit breaker is mounted on the base in which theadjustment plate62 will typically already have been installed by means ofrivets98. These rivets, however, fit sufficiently loosely to allow for translational movement of the plate for respect to the base. The circuit breaker is mounted to the base by installation of fasteners through the apertures provided in the base and adjustment plate, as best illustrated inFIG. 10. With the circuit breaker mounted, but somewhat loosely, the continuous adjustment member in the form of the threadedfastener64 may be adjusted to move the adjustment plate and circuit breaker together upwardly and downwardly with respect to the base and bail. In the illustrated embodiment the rotational movement of theadjustment fastener64 is illustrated byarrow108 inFIG. 9, which results in translational motion as indicated byarrow110. To allow translation, the apertures through which all of the fasteners pass through the base are slotted as indicated byreference numeral112 inFIG. 10. The continuous adjustment is afforded by a shoulder ortab114, or multiple shoulders or tabs formed in the base, and acorresponding tab116 in the adjustment plate. Thus, rotation of the fastener allows for continuous upward and downward translation of the adjustment plate along with the circuit breaker with respect to the base and bail. Once these components are in a desired position, all of the fasteners may be tightened to lock the components into their desired position or relationship. In the event that any subsequent changes are desired, this procedure may be repeated by simply loosening the fasteners, adjusting thecontinuous adjustment fastener64, and re-tightening the mounting fasteners.
• A presently contemplated embodiment for the bail and base components is illustrated inFIGS. 11-13. As noted above, thebail30 comprises aslot44 that receives thetoggle lever46 for operation of the circuit breaker.Sides38 and40 may bound or partially surround the circuit breaker and particularly thevents50 on the sides of the circuit breaker. Venting gas will have no detrimental effect, particularly in view of the insulative material of which the bail and base are made. Here again, as noted above,pivot apertures56 are shown in the sides of the bail, and these interface with the pivot pins58 of the base. In the illustrated embodiment, inclines118 are formed on each of these pins to allow arecess120 at corresponding locations on the bail to be slid over the pin, deforming the sides of the bail slightly until the bail snaps into engagement on the base. To limit nuisance movement of the bail in respect to the base, one or more movement resisting features may be provided, such as protrusions or bosses122 (seeFIGS. 12 and 13).
• In the illustrated embodiment, another feature of the bail includes the formation ofintegral linkage slots124 that receive the actuating linkage discussed above (see e.g.,FIG. 2). In the illustrated embodiment these are provided in symmetrical locations on both sides of the bail to allow for linkages to be provided in one or both locations. The bail may also include protrusions or features designed to allow for actuation of auxiliary features. These are illustrated, for example, in the form of aprotrusion126 inFIG. 12 and aside protrusion128 inFIG. 113. As will be appreciated by those skilled in the art, auxiliary switches (removed for clarity) may be mounted to the circuit breaker itself, or to the base, or to any surrounding structure and may be used to provide a confirmation signal of the operational state of the circuit breaker by reference to the position of the bail. Thus, as the bail is raised or lowered, theprotrusions126 and128 may actuate (close) and de-actuate (open) one or more auxiliary switches.
• Among the various alternative structures and systems that the foregoing techniques enable is a 4-pole version of the cover (and other operating components).FIGS. 14-16 illustrate a presently contemplated embodiment for a gas directing cover designed for 4-pole circuit breakers. As seen inFIG. 14, 4-polegas directing cover130 may be fitted to a 4-pole circuit breaker132, the breaker being constructed in a similar manner to the 3-pole version illustrated in the preceding figures, but wider, with the additional pole positioned adjacent to the first three. In this configuration, the 4-polegas directing cover130 may comprise the 3-pole cover48 supplemented by an add-onextension134. Similar structures are provided in this extension, along with the same gas separation and directing features and functionality as in the 3-pole embodiment. As shown inFIG. 15, the extension may include agas venting aperture72, andknockouts74 on a terminal side. The cover will fit over theterminal section136 and the ventingaperture138 of the additional pole, and operate as the other cover structures will, as described above. As shown inFIG. 16, to facilitate mounting and operation of the extension, amechanical receiver140 may be formed on the 3-pole cover48 that receives correspondingtabs142 of the extension. This arrangement enables the two bodies to be joined securely to one another, allows the end wall of the 3-pole cover to serve as a separator, and allows the same 3-pole cover to serve for both 3-pole applications and 4-pole applications without otherwise altering the structure of the 3-pole cover or requiring manufacture of different 3-pole versions.
• While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims (20)

1. A circuit breaker gas directing system, comprising:

an insulative plastic housing configured to be fitted over a gas-venting portion of a circuit breaker;

phase separating partitions disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase;

gas directing partitions separating each venting section from a phase terminal sections for each respective phase; and

apertures communicating each venting section with the surrounding environment.

2. The system ofclaim 1, wherein the housing, the phase separating partitions, and the gas directing partitions are made of the same insulative plastic.

3. The system ofclaim 1, wherein the plastic housing, the phase separating partitions, and the gas directing partitions comprise a single molded piece.

4. The system ofclaim 1, wherein the housing has a height of approximately 25 mm.

5. The system ofclaim 1, wherein the housing comprises knockouts for accessing terminals disposed in the phase terminal sections when the system is installed on a circuit breaker.

6. The system ofclaim 5, wherein when the knockouts are removed, openings are produced in the housing that have a width of not more than approximately 12 mm.

7. The system ofclaim 1, wherein the venting sections are shaped to channel gas venting from the circuit breaker in a generally 90 degree bend.

8. The system ofclaim 7, wherein the venting sections are shaped to contain venting gas and thereby to limit a rate of rise of gas pressure on a surround environment side of the apertures.

9. The system ofclaim 1, wherein the housing comprising engagement rails configured to slidingly engage channels on the circuit breaker at least along boundaries of the venting sections.

10. A circuit breaker gas directing system, comprising:

an insulative plastic housing configured to be fitted over a gas-venting portion of a circuit breaker;

phase separating partitions disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase;

gas directing partitions separating each venting section from a phase terminal sections for each respective phase; and

apertures communicating each venting section with the surrounding environment;

wherein the venting sections are shaped to contain venting gas and thereby to limit a rate of rise of gas pressure on a surround environment side of the apertures; and

wherein the plastic housing, the phase separating partitions, and the gas directing partitions comprise a single molded piece.

11. The system ofclaim 10, wherein the housing has a height of approximately 25 mm.

12. The system ofclaim 10, wherein the housing comprises knockouts for accessing terminals disposed in the phase terminal sections when the system is installed on a circuit breaker.

13. The system ofclaim 12, wherein when the knockouts are removed, openings are produced in the housing that have a width of not more than approximately 12 mm.

14. The system ofclaim 10, wherein the venting sections are shaped to channel gas venting from the circuit breaker in a generally 90 degree bend.

15. The system ofclaim 10, wherein the housing comprising engagement rails configured to slidingly engage channels on the circuit breaker at least along boundaries of the venting sections.

16. A circuit breaker gas directing system, comprising:

a circuit breaker having phase vents that vent gas upon operation of the circuit breaker; and

a cover fitted over the phase vents and comprising an insulative plastic housing, phase separating partitions disposed in the housing and separating three venting sections from one another, one venting section being defined for each respective electrical phase, gas directing partitions separating each venting section from a phase terminal sections for each respective phase, and apertures communicating each venting section with the surrounding environment.

17. The system ofclaim 16, wherein the housing, the phase separating partitions, and the gas directing partitions are made of the same insulative plastic.

18. The system ofclaim 16, wherein the plastic housing, the phase separating partitions, and the gas directing partitions comprise a single molded piece.

19. The system ofclaim 16, wherein the venting sections are shaped to channel gas venting from the circuit breaker in a generally 90 degree bend.

20. The system ofclaim 19, wherein the venting sections are shaped to contain venting gas and thereby to limit a rate of rise of gas pressure on a surround environment side of the apertures.

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